1. Field of the Invention
This invention relates to a method for compressing the signals of several channels such as signals of L channel and R channel, to a compressed signal storing device, and to an electronic musical instrument using the device.
2. Description of the Prior Art
The technology to convert the signals of several channels such as stereo signals to the digital signals such as PCM data is especially applied for storing these signals in the memory. The memory in which the PCM data is stored can be used, for example, for the electronic musical instrument. Formerly, the memory in which the PCM data is stored is corresponding to each channel, and the data of each memory is read to perform individually DA conversion when signals of all channels are reproduced. For instance, several memories (i.e., Japanese utility model laid open sho 59-166293) which store the musical tone waveform data for each channel are provided as sound source, the musical tone data corresponding to the key pressed by the player is individually read from the memories, and these musical tone data are converted to the analog signals through the DA converter to get sound.
Since the memory is individually corresponded to each channel, this conventional system needs "memories.times.N" where N is the number of channels. Moreover, the time required to digitize and transmit the signal is equal to "transmission time for one channel.times.N" where N is the number of channels.